JP4136442B2 - Bead plate for metal gasket and metal gasket - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bead plate used for a metal gasket that is inserted between a cylinder head and a cylinder block of an engine to perform sealing, and a metal gasket using the bead plate.
[0002]
[Prior art]
For example, a metal gasket is generally used as a sealing means used for sealing between a cylinder head and a cylinder block of an automobile engine. These metal gaskets have a single-layer structure using only one bead plate having a bead constituting a seal portion, or a combination of this bead plate and another sub-plate (folded plate, adjustment plate, etc.). Various things, such as a structure, have been put into practical use.
[0003]
FIG. 4 shows typical bead plates for these metal gaskets. The metal gasket bead plate 11 is provided with cylinder holes (bore holes) 12 corresponding to the number of cylinders of the engine, and a bead 13 is formed so as to surround the cylinder hole (bore hole). A plurality of bolt holes 16 are provided for fixing the metal gasket between the cylinder head and the cylinder block.
[0004]
In addition, the actual bead plate is provided with holes for passage of lubricating oil and cooling water, and a bead for sealing them is provided and has a complicated shape. Is not shown.
[0005]
The bead 13 is a portion formed by pressing a flat bead plate 11 so as to have a trapezoidal or substantially semicircular cross section. The bead 13 is a metal gasket formed only by the bead plate 11 or the bead plate 11 and other auxiliary plates. When a metal gasket formed by overlapping plates (folding plate, adjustment plate, etc.) is sandwiched between a cylinder head and a cylinder block and tightened with a bolt, the convex portion of the bead 13 receives the pressure, The space between the members on the top side surface is sealed, and the space between the other surface members is sealed at both bottom end portions (hem portions) of the beads 13.
[0006]
In order to make the sealing by the bead 13 more reliable, it is generally performed to apply a coating material to the bead 13 and a predetermined range on both sides thereof.
[0007]
Also, when the metal gasket is sandwiched between the cylinder head and the cylinder block and tightened with a bolt, an excessive force is applied to the bead 13 to prevent the bead from sagging or losing the sealing performance. A stopper member is provided to limit the deformation amount of the bead 13.
[0008]
[Problems to be solved by the invention]
However, the method of forming the stopper separately from the bead as described above has a problem that the process becomes complicated and the cost increases accordingly. Further, when the distance from the bore hole end to the bead becomes small as the engine is downsized, it is difficult to provide a stopper separately from the bead.
[0009]
As a method for solving such a problem, a method has been proposed in which a hard resin or metal powder is applied to the concave portion of the bead (that is, the back side of the bead forming the convex portion), thereby acting as a stopper. Yes. However, this method has a problem that a hard resin or metal powder portion has poor sealing performance, and a sealing material must be separately applied to this portion.
[0010]
In addition, even if the stopper is provided separately from the bead as described above, or the hard resin or metal powder is applied to the bead portion in this way to serve as a stopper, both the bead top and the bottom of the bead are on the mating surface. The situation where the surface pressure increases due to the strong hit is not much different. This high surface pressure provides high sealing performance, but on the other hand, the bead is easy to sag, indentation occurs on the mating surface, and when using a rubber-based sealing material, sag, flow or crushing, etc. There is a problem of causing.
[0011]
As a method for preventing such a problem from occurring, there is a method in which the sealing material has a role as a stopper by making the thickness of the sealing material itself in the bead portion larger than the thickness of the other flat portion. -68281.
[0012]
However, when this method is to be carried out, since the sealing material can be easily stored in the concave portion of the bead (described in JP-A-9-68281 as the back surface of the top of the bead), the thickness of the sealing material in this portion Although it is easy to increase the thickness, the skirt portion on the side of the bead (described in Japanese Patent Laid-Open No. 9-68281 as the opposite surface of the bead base) is flat, so that the sealing material flows. As a result, the thickness becomes thinner than intended, and there has been a problem that the coating has to be performed twice in order to obtain a desired thickness.
[0013]
The present invention has been made in view of such circumstances, and provides a bead plate for a metal gasket that can reliably cause the sealing material to serve as a stopper, and a metal gasket using the bead plate. Let it be an issue.
[0014]
[Means for Solving the Problems]
A first means for solving the above-described problem is a bead plate used for a metal gasket that is inserted between a cylinder head and a cylinder block of an engine and performs sealing , and at least one of the beads in an unloaded state. Part of the bead has a shape that protrudes in a direction opposite to the direction of the bead, and a portion located on one side or both sides of the bead has a shape that is opposite to the direction of the bead and the direction of the bead. A metal gasket bead plate (Claim 1), characterized in that a coating material is coated thicker than other portions in a concave portion of a portion having a convex shape.
[0015]
This means is different from the bead plate described in JP-A-9-68281 in that at least a part of the bead has a skirt portion located on one side or both sides of the bead in the direction of the bead. And having a shape that is convex in the opposite direction. That is, the bead plate described in Japanese Patent Laid-Open No. 9-68281 is different from the conventional bead plate in that the bead portion has convex portions and both sides thereof are flat. , At least one skirt portion of the bead portion is convex in a direction opposite to the bead.
[0016]
If it does in this way, a recessed part will be formed in the opposite side which is a convex part also in the skirt part of the side of a bead, and a coating material (sealing material) can be collected in the concave part. Therefore, the problem of the bead plate described in Japanese Patent Laid-Open No. 9-68281, in which the sealing material flows at the skirt portion of the bead and the thickness thereof cannot be increased, is eliminated. In the bead portion and the skirt portion, the coating material is eliminated. Can be applied thick enough to serve as a stopper.
[0017]
The second means for solving the problem is the first means, and has a shape that is convex in the direction opposite to the concave portion of the bead portion and the direction of the bead in an unloaded state. The coating material coated in the concave portion of the portion is formed by applying the bead and the coating material applied in the vicinity thereof so that the average thickness is 10 μm or more. (Claim 2).
[0018]
When applying a coating material to be coated on these parts, if the average thickness is 10 μm or more, the coating material tends to accumulate in each recess, and the coating material thickness of the target part is increased. It becomes easy. If the average thickness is less than 10 μm, it is difficult for the coating material to accumulate in each recess, and the coating material thickness may not be increased as intended.
[0019]
In particular, when applied so that the average thickness is 20 to 40 μm, the thickness of the coating material formed in each recess can be made to be just a good thickness to reliably serve as a stopper, More preferred.
[0020]
The third means for solving the above-mentioned problem is the first means or the second means, and in a no-load state, the concave portion of the bead portion and the convex direction in the direction opposite to the direction of the bead. The viscosity of the coating material coated on the concave portion of the portion having the shape as described above is 30000 cP or less at the time of application (claim 3).
[0021]
When the viscosity of the coating material is 30000 cP or less at the time of application, the coating material can easily flow and accumulate in the concave portion, and the coating film thickness in the target concave portion can be naturally increased. If it exceeds 30000 cP, the fluidity of the coating material becomes poor and it is difficult for the coating material to accumulate in the recesses, and the coating film thickness in the recesses may not be sufficiently increased.
[0022]
It is particularly preferable that the viscosity of the coating material is 10,000 to 20000 cP at the time of application, since the thickness of the coating material that flows and accumulates in the concave portion is an appropriate thickness to serve as a stopper.
[0025]
It said fourth means for solving the problems is the first means from the third metal gasket comprising a bead plate for the metal gasket is either means (claim 4).
[0026]
This means is constituted by the metal gasket bead plate alone which is one of the first means to the fourth means, or is formed by combining this bead plate and another auxiliary plate. . In any case, the functions and effects of the first to fourth means can be exhibited.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Also in the present invention, the basic configuration of the bead plate is not different from the conventional configuration shown in FIG. 4, so FIG. 4 is referred to and the shape of the AA cross section (bead portion) is shown in FIG.
[0028]
FIG. 1 (a) is a diagram showing in detail the unloaded state and the compressed state of the portion corresponding to the AA cross section of FIG. 4 of the bead plate according to the first embodiment of the present invention. It is. The left end surface of the bead plate 11 in the drawing is a bore hole 12, and a coating material 14 is applied to the front and back surfaces of the bead plate 11. The bead 13 of the bead plate 11 has an upwardly convex shape, but a concave portion (a concave portion on the upper side in the drawing) 15 is formed in the bottom portion of the left side in the drawing. And the thickness of the coating material 14 forms the thick part 14a, 14b thicker than another part in the recessed part which is the back side of the bead 13, and the part of the said recessed part 15, respectively.
[0029]
As shown in FIG. 1A, when the bead plate 11 is clamped between the cylinder head 17 and the cylinder block 18, the bead 13 is crushed and deformed. Then, the thick portions 14a and 14b serve as stoppers and no further deformation occurs. That is, although the coating material 14 undergoes some elastic deformation and plastic deformation, the resistance force when the coating material 14 is elastically deformed and plastically deformed is larger than the resistance force when the bead 13 is deformed. The amount of compression of the coating material is reduced and serves as a stopper.
[0030]
FIG.1 (b) is the same figure as (a) which showed in detail the part (bead part) corresponding to the AA cross section of FIG. 4 of the bead board which is the 2nd Embodiment of this invention. is there. The left end surface of the bead plate 11 in the drawing is a bore hole 12, and a coating material 14 is applied to the front and back surfaces of the bead plate 11. The bead 13 of the bead plate 11 has an upwardly convex shape, and a concave portion (a concave portion on the upper side in the figure) 15 is formed at the skirt portions on both side surfaces thereof. The coating material 14 has thick portions 14 a, 14 b, and 14 c that are thicker than the other portions in the concave portion on the back side of the bead 13 and the concave portion 15.
[0031]
As shown in FIG. 1B, when the bead plate 11 is clamped between the cylinder head 17 and the cylinder block 18 and tightened, the bead 13 is crushed and deformed. Then, the thick portions 14a, 14b, and 14c serve as stoppers and no further deformation occurs.
[0032]
The present embodiment is different from the first embodiment in that concave portions are formed in the skirt portions on both sides of the bead 13 and there is a thick portion 14c. Accordingly, the stopper function and the sealing performance are better than those of the first embodiment.
[0033]
FIG. 1C shows a detailed view of the AA cross section of the bead plate described in JP-A-9-68281 as a comparative example. In this comparative example, since the recesses are not formed in the skirts on both sides of the bead 13, the thick part 14 a of the coating material is formed in the recess on the back side of the bead 13, but the skirts on both sides of the bead 13. In this case, since the thick part of the coating material is not formed to a desired thickness, the stopper function and the sealing function of the coating material are inferior to those of the embodiment of the present invention.
[0034]
When the bead plate 11 is sandwiched between the cylinder head 17 and the cylinder block 18 and tightened as shown in FIG. 1C, the bead 13 is crushed and deformed. In this case, only the thick portion 14a serves as a stopper, and a gap is formed between the bead 13 and the coating material of the skirt portion, so that the bead portion 13 is more easily crushed and compared with the present invention. It is easy to produce.
[0035]
In the drawings at the time of compression in FIGS. 1A and 1B, the thick coating portions 14a, 14b, and 14c are drawn so that they are completely in contact with the mating surface. It is not necessary to hit the other side, and it is sufficient if it can be used as a stopper.
[0036]
That is, in the bead plate described in JP-A-9-68281, only the thick portion 14a is often formed, and in some cases, portions corresponding to the thick portions 14b and 14c are formed. However, it is difficult to achieve the desired thickness. On the other hand, in the embodiment of the present invention, the thick portion 14b or the thick portions 14b and 14c are reliably formed, so that these serve as a stopper as in the case of 14a, and the effect is increased. The pressure receiving area of the skirt portion of the bead portion is increased, the coating sag is reduced, and a coating material having both excellent stopper function and sealing function can be obtained.
[0037]
FIG. 2 shows an example of a method for forming the bead portion shown in FIG. First, a bead is formed by pressing the bead plate 11 between an upper die 21 having a convex portion 21a and a lower die 22 having a concave portion 22a (a).
[0038]
Next, the bead plate 11 on which the beads are formed is leveled. As shown in (b), this is done by sandwiching and pressing the bead plate 11 on which the bead is formed between the upper die 23 and the lower die 24. At this time, the portion corresponding to the bore hole of the bead plate Is pressed against the side surface of the convex portion 24a of the lower mold 24 to perform pressing. As a result, as shown in (c), a bead plate 11 is formed in which a recess (when the bead 13 is convex) 15 is formed on the bore hole 12 side of the bead 13. At this time, the concave portion 15 is formed on the bore hole side because the bore hole portion that is to be spread laterally at the time of pressing is constrained by the side surface of the convex portion 24a and cannot be spread laterally. It is.
[0039]
In this state, the coating material 14 is applied over the bead 13 and both sides thereof. Then, the coating material 14 flows along the slope and accumulates in the concave portion of the bead 13, and a thick portion 14 a is formed in this portion as shown in FIG.
[0040]
When the coating material is dried, the bead plate 11 is turned over, and the bead 13 and the coating material 14 are applied to both sides of the bead plate 11 with respect to the upper surface. Then, the coating material 14 flows along the slope and accumulates in the recess 15, and a thick portion 14 b is formed in this portion as shown in FIG. If the coating material is dried in this state, a bead portion having a structure as shown in FIG.
[0041]
FIG. 3 shows an example of a method for forming the bead portion shown in FIG. First, a bead is formed by pressing the bead plate 11 between an upper die 21 having a convex portion 21a and a lower die 22 having a concave portion 22a (a).
[0042]
Next, the bead plate 11 on which the beads are formed is leveled. As shown in (b), this is done by sandwiching and pressing the bead plate 11 on which the bead is formed between the upper die 23 and the lower die 24. At this time, the portion corresponding to the bore hole of the bead plate Is pressed against the side surface of the convex portion 24a of the lower mold 24, and pressing is performed so that the portion opposite to the bore hole against the bead contacts the convex portion 24b of the lower mold 24. As a result, as shown in (c), a bead plate 11 is formed in which concave portions (when the beads 13 are convex) 15 are formed on both sides of the beads 13. At this time, the concave portion 15 is also formed on the side of the bore hole having no convex portion in the lower mold 24. The reason is that the side of the convex portion 24a restrains the bore hole portion that is about to spread laterally during pressing. Because it cannot spread sideways.
[0043]
In this state, the coating material 14 is applied over the bead 13 and both sides thereof. Then, the coating material 14 flows along the slope and accumulates in the concave portion of the bead 13, and a thick portion 14 a is formed in this portion as shown in FIG.
[0044]
When the coating material is dried, the bead plate 11 is turned over, and the bead 13 and the coating material 14 are applied to both sides of the bead plate 11 with respect to the upper surface. Then, the coating material 14 flows along the slope and accumulates in the recess 15, and thick portions 14 b and 14 c are formed in this portion as shown in FIG. If the coating material is dried in this state, a bead portion having a structure as shown in FIG. 1B is formed.
[0045]
As the coating agent used in the present invention, known rubber materials and resin materials such as epoxy resins and phenol resins can be used. However, it is preferable to use a resin composition (Japanese Patent Application No. 2002-47954) filed earlier by the present applicant as the resin-based material because it can exhibit particularly excellent characteristics in the present invention. One of such materials is a filler having a solid lubricating effect of 50 to 250 parts by weight with respect to a total of 100 parts by weight of a thermoplastic polymer compound having a glass transition temperature of 150 ° C. or less and a thermosetting resin. It is what was added.
[0046]
In this coating agent, a sealing property is secured by a thermoplastic polymer compound having a glass transition temperature of 150 ° C. or lower, and heat resistance is secured by a thermosetting resin. Addition of a thermoplastic polymer compound to a thermosetting resin increases the friction coefficient and decreases slipperiness, but by adding a filler having a solid lubricating effect to these, the friction coefficient is reduced and good slipperiness is achieved. Is secured. This filler may not only lower the coefficient of friction but also have the effect of further improving the sealing performance. However, if the amount of the filler is out of the range of 50 to 250 parts, the sealing property may be hindered. Therefore, in this coating agent, the ratio of the filler is limited to this range.
[0047]
Similarly, the coating agent used in the present invention is a mixture of at least one resin having a glass transition temperature of 150 ° C. or lower and at least one resin having a glass transition temperature or a melting temperature exceeding 150 ° C. What added 50-250 weight part of filler which has a solid-lubricating effect with respect to 100 weight part is also preferable.
[0048]
In this coating agent, by using a mixture of at least one kind of resin having a glass transition temperature of 150 ° C. or less and at least one kind of resin having a glass transition temperature or a melting temperature exceeding 150 ° C. The glass transition temperature is ensured with a resin having a glass transition temperature of 150 ° C or lower, and the heat resistance is ensured with a resin having a glass transition temperature or a melting temperature exceeding 150 ° C. Can be.
[0049]
Furthermore, in the above two types of coating agents, the material constituting the filler is a solid having a hexagonal crystal structure such as graphite or molybdenum disulfide, or a coefficient of friction in air such as molybdenum trioxide or zinc oxide. Is preferably a solid single species of 0.6 or less, or a combination of a plurality of these.
[0050]
In addition, it is preferable to add one or more of carbon, talc, and clay to the filler of the coating agent for metal gasket because the heat resistance of the coating agent can be increased.
[0051]
These resin compositions are superior to conventional rubber-based coating materials in terms of slipperiness, are less likely to cause crushing and flow, and have better sealing properties than conventional resin-based coating materials. When the structure for storing the coat is used as described above, high sealing performance and excellent stopper function can be stably maintained over a long period of time.
[0052]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a metal gasket bead plate that can reliably serve as a stopper to the sealing material, and a metal gasket using this bead plate.
[Brief description of the drawings]
FIG. 1 is a detailed view of a bead portion of a bead plate according to first and second embodiments of the present invention.
FIG. 2 is a diagram showing an example of a method for forming a bead portion shown in FIG.
FIG. 3 is a diagram showing an example of a method for forming a bead portion shown in FIG.
FIG. 4 is a view showing an outline of a bead plate for a typical metal gasket.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Bead board, 12 ... Bore hole, 13 ... Bead, 14 ... Coating material, 14a, 14b, 14c ... Thick part, 15 ... Concave part, 21 ... Upper mold | type, 21a ... Convex part, 22 ... Lower mold | type, 22a ... Concave part, 23 ... upper mold, 24 ... lower mold, 24a ... convex part, 24b ... convex part

Claims (4)

A bead plate used for a metal gasket that is inserted between a cylinder head and a cylinder block of an engine and seals it, and in an unloaded state, at least a part of the bead, on one side or both sides of the bead The skirt portion positioned has a shape that is convex in the direction opposite to the direction of the bead, and the concave portion of the bead portion and the portion that has a shape that is convex in the direction opposite to the direction of the bead. A bead plate for a metal gasket, wherein the concave portion is coated with a coating material thicker than other portions. It is a bead board for metal gaskets of Claim 1, Comprising: It coats the recessed part of the part which has a shape which becomes convex in the reverse direction to the direction of the bead, and the recessed part of the bead part in an unloaded state. The metal gasket bead is characterized in that the coating material formed is formed by applying a bead and a coating material applied in the vicinity thereof so that the average thickness thereof is 10 μm or more. Board. It is a bead board for metal gaskets of Claim 1 or Claim 2, Comprising: The part which has a shape which becomes convex in the recessed direction of the said bead part, and the direction opposite to the direction of the said bead in an unloaded state. A bead plate for a metal gasket, characterized in that the viscosity of the coating material coated on the concave portion is 30000 cP or less at the time of application. A metal gasket comprising the bead plate for a metal gasket according to any one of claims 1 to 3 .

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